Detonator cap assembly for firearm cartridges

ABSTRACT

A detonator cap assembly is provided for firearm cartridges which may be detonated either by an electrical impulse or by percussion means. A cap of electrically conductive material is mounted within a cartridge casing and encloses a fulminating material. The cap is electrically insulated from the cartridge casing and a thin electrically conductive priming wire is connected between the cartridge casing and the cap to detonate the fulminating material when an electrical current is passed therethrough. The cap is also capable of detonation by a conventional firing pin.

Jakobs et al.

1 1 Oct. 29, 1974 [54] DETONATOR CAP ASSEMBLY FOR 3,719,148 3/1973 Gawlick at al 102/46 FIREARM RT I G 3.7685113 l0/l973 Ramsay I02/46 [76] Inventors: Ferdinand l akobs lilarignstrassg 5, FOREIGN PATENTS OR APPLICATIONS 66 1 Uwe Heinrich 4,449 7/1910 Great Britain 102/46 Sewing, Neuklef, 5276 Wiehl 1, both of Germany Primary Examiner-Benjamin A. Borchelt [22] Filed: June 18, 1973 Assistant ExaminerC. T. Jordon At! ,A r, F -T n,MG d&St 1 pp 6 orney gen 0r lrm ore c ea y anger 0 [57] ABSTRACT [30] Foreign Apphcatlon Pmmty Data A detonator cap assembly is provided for firearm car- June 30, 1972 Germany 2232049 tridges which y be detonated eithm. y an electric?! impulse or by percussion means. A cap of electrically [52] US. Cl. 102/46 Conductive material is mounted within a cartridge [5i] [lit- Cl F42) 9/08 g and encloses a l i g materiaL The p is [58] held of Search 102/46 28 28 EB electrically insulated from the cartridge casing and a thin electrically conductive priming wire is connected [56] References between the cartridge casing and the cap to detonate UNITE STATES PATENTS the fulminating material when an electrical current is 7l2,826 11/ 1902 Mason 102/46 passed therethrough. The cap is also capable of deto- 1,034,160 7/1912 Starkweather... 102/46 nation by a conventional firing pin. 2 980,0l9 4/1961 Noddin I. 102/28 EB 0 3,363,565 1/1968 Walther 102/46 25 Clams, 12 Drawmg Flglll'es V w f v.- 1 w *1 fi 7"' J I 5 772/ 4 4r raw/19 W 7 1 7 i 4Z 1 0. 0/

DETONATOR CAP ASSEMBLY FOR FIREARM CARTRIDGES BACKGROUND OF THE INVENTION The present invention relates generally to firearm cartridges and more specifically to the type of cartridge which can be detonated either by electrical impulse or by percussion. The invention is particularly concerned with a detonator cap assembly for such a cartridge.

Firearm cartridges capable of detonation either by electrical impulse or by percussion priming have been heretofore known. In one prior art device, the primer composition is made electrically conductive by the admixture of materials such as graphite. The graphite is arranged in a metal cap which is insulated from the cartridge shell and an anvil used for percussion timing bears against against the metal cap and operates as a second pole to form an electrically conductive connection to the inserted metal cap. It has been found, however, that this type of device requires a relatively large amount of electrical energy for its detonation due to the fact that the graphite particles are added in an unoriented manner to the fulminating material and, therefore, an electrical path of high resistivity exists. In the case of a hand gun, the current source required for detonation must be arranged within the firearm itself. In addition, the striking point of the firing pin percussion cap opposite the anvil must be arranged, for construction reasons, at such a distance inside the cap that the firing pin projects too far from the breech pin forming the abutment of the cartridge thereby impairing the operation of the weapon. Furthermore, when the detonator cap is inserted in the cartridge, there is a danger that, due to unavoidable measuring tolerances, the pressure of the anvil on the fulminating material will become too high and the weapon will be accidentally detonated.

In another known prior art device capable of detonation by electrical priming, the detonator cap which is inserted into the cartridge casing consists of a conductive pin surrounded with insulating material for the priming wire between the insulating material and the cartridges. In this device, where an electrical priming is provided for only by means of a filament, there is a danger that the centrally arranged conductive pin, which is merely pressed into the insulating body, will be dispelled by high pressure powder gases formed during the priming.

SUMMARY OF THE INVENTION The present invention is particularly suited as a detonator cap for cartridges which can be fired by both electrical means and by percussion means such as a firing pin. Furthermore, the invention may be utilized as a detonator cap for cartridges used in hand-held firearms without requiring replacement or restructuring of any of the parts of such commercial firing pin weapons or cartridge casings. Cartridges equipped with the detonator cap of the present invention are particularly adaptable for use with more modern weapons involving detonations which are characterized, in contrast to firing pin weapons, by the fact that the very complicated and expensive mechanical breech mechanisms are eliminated or replaced by simple electrical switching elements. This not only increases the safety of the weapon but it also makes misfiring virtually impossible.

The detonator cap according to the present invention may be used in central fire cartridges sometimes referred to in the art as center fired cartridges" as a replacable cap provided with a priming wire. The detonator cap assembly includes a detonator cap mounted in a cartridge casing which encloses fulminating material. The detonator cap is configured in such a manner that, when used in commercially available hand firearms, it may be detonated by a conventional firing pin. A thin, short electrically coductive priming wire, which may be preferably made of corrosion resistant material such as magnesium, extends within the detonator cap through the fulminatimg material. The detonator cap is made of electrically conductive material and it is insulated from the cartridge casing. Thus, the primer wire may extend from the detonator cap to the cartridge casing and may be used to ignite fulminating material when a small current impulse is passed therethrough.

In another embodiment of the invention, which may be utilized with rim-fired cartridges as well as with central-fired cartridges, the priming wire is applied on a lamina which is inserted into the detonator cap. In rimfired cartridges, where the detonator cap represents an integral part of the cartridge casing, the priming wire is mounted within the cartridge casing and is inserted as a prefabricated part thereof into the cap or case being held there by clamping or pasting.

A particular advantage of the present invention resides in the fact that the detonator cap may be detonated with relatively small amounts of electrical energy and it will be found adaptable for use with practically all commercial firing pin weapons. With the present invention there is no need to alter the structure of presently used central-fire cartridges, which can be conventionally reloaded as often as is desired. Furthermore, as a result of a plastic and varnish coating which, in accordance with the present invention, is applied to surround the detonator cap laterally, the present invention provides a structure which is corrosion proof due to the reliable seal formed by this coating. By an appropriate selection of the material of the priming wire, which may be formed with or without an armoring primer pellet, relatively short detonation times may be achieved compared to presently known percussion detonation and misfiring is virtually eliminated.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawing and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a sectional view of a detonator cap according to the present invention mounted in a cartridge cas ing wherein electrical contact with the casing is established through a contact stud attached to the priming wire;

FIG. 2 is a sectional view showing a detonator cap with a firing pin which is inserted from the exterior thereof;

FIG. 3 is a top view of the embodiment shown in FIG.

FIG. 4 shows a detonator cap with a contact pin extending through an insulated anvil;

FIG. 5 is a sectional view of a detonator cap wherein a contact is formed utilizing the anvil;

FIG. 6 is a sectional view showing another embodiment of a detonator cap of a central-fire type cartridge;

FIG. 7 is a bottom view of a perforated sheet covered with priming wires from which individual priming lamina may be punched out;

FIG. 8 is a top view of the central-fire type detonator cap of FIG. 6 showing a single priming lamina;

FIG. 9 is a sectional view of the lamina shown in FIG.

FIG. 10 is a sectional view of an embodiment of the detonator cap of the present invention adaptable for use with rim-fire cartridges;

FIG. I] is a top view of the embodiment shown in FIG. 10; and

FIG. 12 is a top view showing a priming lamina for rim-fire priming.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. I there is shown a detonator cap assembly according to the present invention comprising a cup shaped metal detonator cap 1 which is press fitted in a conventional manner into the bottom of a cartridge casing 2. A fulminating material 3 is contained within the cap 1 and a priming wire 4, which may be formed of magnesium or other suitable material, extends within the cap I through the fulminating material 3. The fulminating material 3 is of a type which may be percussively detonated. The material of the priming wire 4 is selected to be of the type which will burn readily by flash ignition when a small amount of electrical energy is applied thereto. An anvil 5 which will serve as an abutment for a firing pin when the cartridge is detonated by percussive means, is also included in the detonator cap assembly shown. The fulminating composition is coated in a conventional manner similar to that heretofore known for detonator caps of the percussion type, with a thin covering lamina 6. Furthermore, the priming wire 4 may be additionally armored in a known manner shown in connection with the embodiment of FIG. 4, with a primer pellet 7 which burns very rapidly and with great heat when current is applied.

The cap 1 is insulated from the cartridge casing 2 by a varnish or plastic coating 8. To the interior of the cap 1 and/or on the anvil 5, there is secured one end of the priming wire 4 either directly or through a special lead wire, for example, by soldering or clamping. The casing 2 which represents one pole of the electrical circuit including the priming wire 4 has the priming wire connected thereto in a manner to form a good and permanent contact. This contact is applied by resilient means and may be effected in various ways according to the invention.

In the embodiment shown in FIG. I, the free end of the priming wire 4 is armored with a resilient tongue 13 which is insulated between the anvil 5 and the cap I and which is positioned to abut against the bottom of the casing 2. The opposite end of the priming wire 4 may also be clamped conductively between the anvil and the cap and extends from this connection through the fulminating material 3 to the resilient tongue.

Manufacturing advantages which may be achieved with the present invention are illustrated in the embodiment of FIGS. 2 and 3. In this embodiment, a firing pin 14 is press fitted from exteriorly thereof into a recess of the anvil 5. The firing pin 14 consists of an insulating body 15, which is armored with two separate, electrically conductive layers 16 and 17, of which one, the layer 16, is pressed on the inside of the cap I and/or the anvil 5. The second layer 17 terminates in a metallic contact 18 which is positioned to press against the bottom 10 of the casing 2. The distance between these two conductors is bridged by the thin priming wire 4 which extends through the fulminating composition 3.

In an embodiment according to FIG. 4, the free end of the priming wire is clamped in a recess of the anvil 5 by a pin 9 which has an outwardly directed point resiliently bearing on the bottom 10 of the cartridge casing 2. The anvil 5 is again insulated from the cap 1 by a varnish or plastic coating 11. In the embodiment according to FIG. 5, one or several of the webs of the anvil 5 are formed to comprise a protruding member 12 which is arranged to bear resiliently against the bottom 10 of the casing 2, in a manner similar to those previously described.

Alternatively, the anvil 5 may be insulated from the cap I by a raised edge of the covering lamina 6 which extends across the fulminating material and which is interposed between these two conductive parts.

In order to avoid short circuiting of the upper free edge of cap 1, which could occur if the priming cap is pressed too vigorously into the cartridge casing 2, a thin insulating ring 19 is provided between the cartridge case bottom 10 and the top edge. The ring 19 may also be extended to cover the upper edge of the anvil 5, if this is found necessary.

Another embodiment of the detonator cap assembly of the present invention shown in FIG. 6 comprises a priming lamina 22 which covers the fulminating composition 3 and is clamped between the outer edge of the anvil 5 and the upper stepped edge of the cap 1. The lamina 22 includes a metalized edge 26 and the priming wire 4 extends across the underside of the lamina 22 and is in conductive connection with the cap 1 while the anvil itself is insulated from the cap by the nonconductive surface of the lamina 22. At its lowest point, the anvil 5 passes through a metallic border 27 of a central recess 28 of the priming lamina 22 and is in conductive contact with the priming wire thereat.

The outer top edge of the anvil 5 extends over the upper edge of the cap I and thus it will be in contact with the bottom of the cartridge casing, which is not shown in FIG. 6, when the detonator cap assembly is mounted in the cartridge. Accordingly, current will flow from the cap, which is insulated from the casing in the manner previously described by a varnish coating or the like, through the priming wire 4, thus igniting the fulminating material 3, to the center of the anvil S and therethrough to the cartridge casing.

In order to enable utilization of more economical mass production manufacturing techniques, the priming lamina may be printed and perforated on a large sheet 29 shown in FIG. 7, which may be covered with priming wires 4. This large sheet may then be applied on the detonator caps arranged side by side in a receiver. The detonator caps are filled with the fulminating composition and the sheet 29 is then punched with a multiple punch into the filled caps with appropriate edges being cut at the same time.

In cartridges of the rim-fire type the bottom of a cap 30 shown in FIG. is provided with a recess into which is inserted a differently shaped priming lamina. These priming lamina consist of a metallic sheet 31 whose outwardly extending underside is exposed in the range of the cap bottom recess and is again insulated from the cap bottom by a varnish or other insulating coating 32. The priming wire for covering this lamina 31 can thus be connected centrally with the top side of the lamina 31. The remaining portion of the top side and of the side flanks of this lamina are thus likewise insulated and the free ends of the priming wire are conductively connected with the casing bottom, for example, by clamping between the bottom insulating layer of the lamina 31 and the casing bottom, or by any other appropriate means. For this purpose, the priming lamina is preferably formed with a conductive border 33 which acts as a contact bridge and which is insulated from the lamina but which may also serve to clamp the priming wire.

The connection of the priming wire 4 with the metallic lamina 31 may be effected so that a thin layer of plastic 34 may be used as its upper insulation. A tongue 35 may be formed to extend through a cutout between which the priming wire, bearing on the metal lamina, is clamped. A radially extending spring 36, bearing upon the inner side of the cap shell is arranged to press the priming wire against the contact surface of the metallic lamina. This spring must, accordingly, be formed of non-conductive material. The spring operates to secure the priming lamina against lifting and may also serve as an anvil having an appropriate design if the cartridges are to be fired from weapons having centralfire percussion detonation. However, the radial spring 36 may also be electrically conductive. In such case, the lamina 31 is so insulated on its top side that the priming wire is only in contact with it at its edge and current will accordingly flow from the lamina 31 through this wire and the radial spring to the casing.

In order to prevent lifting of the priming laminae by detonation gases, the casing bottom may be provided with an inwardly pointing corrugation 37 which frames the lamina. In such case, the radial spring will bear preferably against a corrugation 38 formed in the casing surface.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. A detonator cap assembly for firearm cartridges including a cartridge casing of electrically conductive material capable of being alternatively fired by electrical means and by percussion means comprising a detonator cap of electrically conductive material mounted within said cartridge casing and configured to enable percussive detonation thereof, an anvil located between said detonator cap and said casing, a charge of fulminating material contained within said cap between said cap and said anvil, means for electrically insulating said cap from said cartridge casing, a thin electrically conductive priming wire extending within said cap through said charge of fulminating material, and means for conductively connecting said wire betweensaid detonator cap and said cartridge casing.

2. An assembly according to claim 1 wherein said cartridge casing is arranged to serve as a current conductor and wherein said priming wire is attached to resilient means arranged to bear against said cartridge casing.

3. An assembly according to claim 1 wherein said priming wire is electrically connected to an electrically conductive resilient tongue bearing against said cartridge casing to armor said priming wire, with insulating means being provided to insulate said resilient tongue from said anvil and from said detonator cap.

4. An assembly according to claim 1 including a recess formed in said anvil, a firing pin located in said recess in said anvil and pressed into said detonator cap, said firing pin being formed of insulating material, two separately conductive layers armoring said firing pin with one of said conductive layers bearing under pressure upon said detonator cap and with the other of said conductive layers terminating at an electrical contact point.

5. An assembly according to claim 1 wherein said priming wire is electrically connected with said anvil which is insulated from said cap, said anvil being electrically connected with said cartridge casing.

6. An assembly according to claim 1 wherein said anvil is provided with at least one outwardly extending pin which bears against the bottom of the cartridge casing to form an electrical connection therewith.

7. An assembly according to claim 6 wherein said priming wire is secured to said anvil by said pin, said pin being pressed into one side of said anvil.

8. An assembly according to claim 1 wherein said priming wire is attached to said detonator cap by soldering.

9. An assembly according to claim 1 wherein said priming wire is armored with a primer pellet.

10. An assembly according to claim 1 wherein said means electrically insulating said cap from said cartridge casing comprise a varnish coating.

11. An assembly according to claim 1 wherein said means insulating said cap from said cartridge casing comprise a plastic coating.

12. An assembly according to claim 1 wherein said anvil is mounted upon said cap and insulated therefrom by a varnish coating.

13. An assembly according to claim 1 wherein said anvil is mounted upon said cap and insulated therefrom by a plastic coating.

14. An assembly according to claim 1 including a primer lamina covering said anvil on a side thereof proximate said detonator cap, said lamina covering extending to insulate said cap from said anvil.

15. An assembly according to claim 14 wherein said detonator cap comprises an upper terminal edge arranged proximate said cartridge casing bottom when said cap is mounted therein, said assembly including a ring of insulating material arranged between said edge of said cap and said casing bottom.

16. An assembly according to claim 1 including a priming lamina wherein said priming wire is embedded upon said priming lamina and constitutes a prefabricated part of said assembly.

17. An assembly according to claim 16 wherein said priming lamina consists of electrically insulating combustible material, with said priming wire extending in electrical contact between said detonator cap and an uninsulated portion of said anvil, said anvil extending as a conductor to a point between said cartridge casing and an edge of said detonator cap.

18. An assembly according to claim 17 wherein said lamina is formed with an outer edge provided with an electrically conductive coating acting as a contact bridge.

19. An assembly according to claim 18 wherein the anvil is formed in a generally circular configuration having a central recessed portion with said lamina extending across the surface of said anvil on the side of said detonator cap, said lamina being provided at the portion of said central recess with a conductive border which extends from the underside to the top side of said lamina.

20. An assmbly according to claim 1 wherein said cartridge is of the rim-fire type, with the detonator cap being formed at as an integral part of said cartridge casing, said assembly including a lamina which is insulated from said detonator cap and which is applied from the inside thereof on a centrally recessed bottom of said cap being fixed thereat by a mounting means, the outer visible surface of said lamina being polished, said assembly further comprising a priming wire insulated from said lamina and extending upon the top side thereof to establish electrical connection from said lamina to said detonator cap.

21. An assembly according to claim 20 comprising a tongue formed by cutting out a portion of insulating cover forming part of said lamina, said priming wire being held against said lamina by said tongue, said priming wire also extending between points where said wire is clamped as a contact bridge against the bottom of said detonator cap by the bottom and lateral insulation of said lamina directly over a metallic border of said lamina.

22. An assembly according to claim 21 including a nonconductive spring member and a recessed upper lamina cover, said priming wire and said lamina being pressed by said spring member bearing against the inner wall of said cartridge case to said recessed lamina cover.

23. An assembly according to claim 22 including a metallic lamina of a generally circular configuration including edge portions, and upper lamina insulations, said priming wire being connected with said metallic lamina only at the edges thereof and extending over said upper lamina insulation, with said electrically conductive spring member bearing against the inside of said cartridge shell and pressing upon said priming wire.

24. An assembly according to claim 20 wherein said cartridge casing is formed at its bottom with an inwardly pointing corrugation, said lamina being framed by said inwardly pointing corrugation.

25. An assembly according to claim 22 wherein said cartridge casing includes an inwardly pointing corrugation extending about the side thereof, with said spring member bearing against said inwardly pointing corrugation on the interior of said casing. 

1. A detonator cap assembly for firearm cartridges including a cartridge casing of electrically conductive material capable of being alternatively fired by electrical means and by percussion means comprising a detonator cap of electrically conductive material mounted within said cartridge casing and configured to enable percussive detonation thereof, an anvil located between said detonator cap and said casing, a charge of fulminating material contained within said cap between said cap and said anvil, means for electrically insulating said cap from said cartridge casing, a thin electrically conductive prining wire extending within said cap through said charge of fulminating material, and means for conductively connecting said wire between said detonator cap and said cartridge casing.
 2. An assembly according to claim 1 wherein said cartridge casing is arranged to serve as a current conductor and wherein said priming wire is attached to resilient means arranged to bear against said cartridge casing.
 3. An assembly according to claim 1 wherein said priming wire is electrically connected to an electrically conductive resilient tongue bearing against said cartridge casing to armor said priming wire, with insulating means being provided to insulate said resilient tongue from said anvil and from said detonator cap.
 4. An assembly according to claim 1 including a recess formed in said anvil, a firing pin located in said recess in said anvil and pressed into said detonator cap, said firing pin being formed of insulating material, two separately conductive layers armoring said firing pin with one of said conductive layers bearing under pressure upon said detonator cap and with the other of said conductive layers terminating at an electrical contact point.
 5. An assembly according to claim 1 wherein said priming wire is electrically connected with said anvil which is insulated from said cap, said anvil being electrically connected with said cartridge casing.
 6. An assembly according to claim 1 wherein said anvil is provided with at least one outwardly extending pin which bears against the bottom of the cartridge casing to form an electrical connection therewith.
 7. An assembly according to claim 6 wherein said priming wire is secured to said anvil by said pin, said pin being pressed into one side of said anvil.
 8. An assembly according to claim 1 wherein said priming wire is attached to said detonator cap by soldering.
 9. An assembly according to claim 1 wherein said priming wire is armored with a primer pellet.
 10. An assembly according to claim 1 wherein said means electrically insulating said cap from said cartridge casing comprise a varnish coating.
 11. An assembly according to claim 1 wherein said means insulating said cap from said cArtridge casing comprise a plastic coating.
 12. An assembly according to claim 1 wherein said anvil is mounted upon said cap and insulated therefrom by a varnish coating.
 13. An assembly according to claim 1 wherein said anvil is mounted upon said cap and insulated therefrom by a plastic coating.
 14. An assembly according to claim 1 including a primer lamina covering said anvil on a side thereof proximate said detonator cap, said lamina covering extending to insulate said cap from said anvil.
 15. An assembly according to claim 14 wherein said detonator cap comprises an upper terminal edge arranged proximate said cartridge casing bottom when said cap is mounted therein, said assembly including a ring of insulating material arranged between said edge of said cap and said casing bottom.
 16. An assembly according to claim 1 including a priming lamina wherein said priming wire is embedded upon said priming lamina and constitutes a prefabricated part of said assembly.
 17. An assembly according to claim 16 wherein said priming lamina consists of electrically insulating combustible material, with said priming wire extending in electrical contact between said detonator cap and an uninsulated portion of said anvil, said anvil extending as a conductor to a point between said cartridge casing and an edge of said detonator cap.
 18. An assembly according to claim 17 wherein said lamina is formed with an outer edge provided with an electrically conductive coating acting as a contact bridge.
 19. An assembly according to claim 18 wherein the anvil is formed in a generally circular configuration having a central recessed portion with said lamina extending across the surface of said anvil on the side of said detonator cap, said lamina being provided at the portion of said central recess with a conductive border which extends from the underside to the top side of said lamina.
 20. An assmbly according to claim 1 wherein said cartridge is of the rim-fire type, with the detonator cap being formed at as an integral part of said cartridge casing, said assembly including a lamina which is insulated from said detonator cap and which is applied from the inside thereof on a centrally recessed bottom of said cap being fixed thereat by a mounting means, the outer visible surface of said lamina being polished, said assembly further comprising a priming wire insulated from said lamina and extending upon the top side thereof to establish electrical connection from said lamina to said detonator cap.
 21. An assembly according to claim 20 comprising a tongue formed by cutting out a portion of insulating cover forming part of said lamina, said priming wire being held against said lamina by said tongue, said priming wire also extending between points where said wire is clamped as a contact bridge against the bottom of said detonator cap by the bottom and lateral insulation of said lamina directly over a metallic border of said lamina.
 22. An assembly according to claim 21 including a nonconductive spring member and a recessed upper lamina cover, said priming wire and said lamina being pressed by said spring member bearing against the inner wall of said cartridge case to said recessed lamina cover.
 23. An assembly according to claim 22 including a metallic lamina of a generally circular configuration including edge portions, and upper lamina insulations, said priming wire being connected with said metallic lamina only at the edges thereof and extending over said upper lamina insulation, with said electrically conductive spring member bearing against the inside of said cartridge shell and pressing upon said priming wire.
 24. An assembly according to claim 20 wherein said cartridge casing is formed at its bottom with an inwardly pointing corrugation, said lamina being framed by said inwardly pointing corrugation.
 25. An assembly according to claim 22 wherein said cartridge casing includes an inwardly pointing corrugation extending about the side thereof, with said sprIng member bearing against said inwardly pointing corrugation on the interior of said casing. 